Re: Draft response to BT-1

Steve,

The new draft looks good.

	Andy

On 07/10/11 16:20, Steve Harris wrote:
> Ah, thanks, I see what he is getting at now, draft updated at http://www.w3.org/2009/sparql/wiki/CommentResponse:BT-1
>
> - Steve
>
> On 2011-10-07, at 15:26, Andy Seaborne wrote:
>
>>
>>
>> On 07/10/11 13:15, Steve Harris wrote:
>>> Comment:
>>> http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2011Aug/0000.html
>>>
>>> Draft response:
>>> http://www.w3.org/2009/sparql/wiki/CommentResponse:BT-1
>>>
>>> - Steve
>>>
>>
>> The example is a bit more complicated because it involved aggregation and select expressions.
>>
>> An error in an aggregate is not trapped specifically by the aggregate - it's an error.  In the example it's because the select expression that you get an unbound.
>>
>> SELECT ( 1/0 AS ?x ) {}
>>
>> is:
>>
>> -----
>> | x |
>> =====
>> |   |
>> -----
>>
>> this then explains the second point: ?c can be bound if AVG is an error because the AVG error is handled in SELECT expressions.
>>
>> SELECT
>>    ( COALESCE(SUM(?a),"error") AS ?x )
>>    (SUM(?a) AS ?y )
>> { BIND ("abc" AS ?a) }
>>
>> ==>
>>
>> ---------------
>> | x       | y |
>> ===============
>> | "error" |   |
>> ---------------
>>
>> and then HAVING( aggregate error ) is just like a FILTER and error.
>>
>> 	Andy
>>
>

Received on Saturday, 8 October 2011 12:27:13 UTC